Agree the point about West Cumbria - Workington to Newcastle is not an easy drive.
However, I thought that even when 're-developed' CAX won't be able to accept regular operations by 737/319 so rather than Easy/Ryanair/Jet2, the most likely operators would be in the Flybe/Aer Arran/VLM category.
SEN seems the most obvious destination with Stobarts owning both airports.